1. Field of the Invention
The present invention relates generally to motor vehicle headlamps. The invention more specifically relates to an illumination module with which these headlamps can be equipped and which comprises a light source, an elliptical collector which allows the reflection of a beam originating from this source, and a convergent lens in the direction of which the beam is reflected so as to be distributed and projected externally of the headlamp, in front of the vehicle. The light source is disposed substantially in line with the first focal point of the collector.
2. Description of the Related Art
Such modules comprising a light source, a collector and a convergent lens are known, in which, in order to meet standards aimed for example at preventing road users coming from the opposite direction from being dazzled, an lighting beam of the cutoff type is produced. A cutoff beam means a lighting beam which has a directional limit, that is to say the cutoff, beyond which the luminous intensity is reduced. To this end, these modules are equipped with a shield, which is disposed along the path of the light beam, substantially in line with the second focal point of the collector, so as to cut off the potentially dazzling part of the beam. It is therefore necessary to precisely position close to the second focal point the edge of the shield that will delimit the cutoff of the beam, this edge being referred to as the cutoff edge.
Conventionally, such a shield is placed in position in the module by the cooperation of indexing holes formed in the shield and indexing pieces interdependent with a component of the module and is fixed in place by screwing. It is therefore necessary during manufacture of the shield to ensure very precise positioning of the indexing holes in relation to the cutoff edge. In addition, the assembly play which arises with this type of assembly may hinder the precise positioning of the cutoff edge of the shield in the module. This results in a less precise cutting of the light beam exiting from the module. This impaired positioning hinders chromatism, inter alia.